I am working on a high-performance switching system. I the old ones there was no big issue in just touching a gate with an oscilloscope probe, but this time I have high voltage and very short (5nsec) rise/fall time, so I have to think through test points.

I would go for SMA and then connect it with a coax to the scope, but I have no room for that.

So the question is, what are the recommendations for the smallest possible test points to measure fast switching power transistors behavior. Maybe some special probes can be used. What did you fellas do in the past?

Upd: due to the relatively high voltage and small size of the product, i really don't want to touch it while it is working. It has to be something that the probe is nicely attached to it. Additionally the ground of the probe should be very short, ideally it would even be a nice differential probe (although at this point i am most interested in preparing everything in layout).

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    \$\begingroup\$ How high is a "high voltage"? What frequencies are involved? How much current is being switched? What aspect of performance are you trying to measure? \$\endgroup\$ – The Photon May 8 '19 at 16:24
  • \$\begingroup\$ Voltage- 100V to 500V (later to 1000V). Switching frequency around 20-40kHz, but fast rise/fall time. Most interesting is the voltage on all kinds of nodes- VGS, VDS, maybe some other points in the circuit. Currents dont matter much at this point. \$\endgroup\$ – Gregory Kornblum May 8 '19 at 16:29
  • \$\begingroup\$ How about pure capacitive coupling? just bring the probe tip very close. This lets you achieve attenuation, yet preserve the risetimes and pulse flatnesses. \$\endgroup\$ – analogsystemsrf May 8 '19 at 16:42
  • \$\begingroup\$ I am not sure i need attenuation. But the idea is good, allows maybe soldering a wire to cap's pad. \$\endgroup\$ – Gregory Kornblum May 8 '19 at 16:44
  • \$\begingroup\$ You can't just put some appropriate pads on the board and use a high-ratio scope probe like Keysight 10076C? \$\endgroup\$ – The Photon May 8 '19 at 16:59

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